Known piecing methods and apparatuses draw a leading yarn out from a sliver guide entrance of a nozzle constituting a twist device before driving a draft device to resume supplying a sliver while operating the twist device to entangle fibers constituting the sliver with the leading yarn for piecing.
In the conventional piecing method and apparatus, when the yarn is cut, the tip of a sliver torn between a stopped draft roller and an operating draft roller is thinned and tapered. When spinning is resumed, the cut end of the thinned and tapered sliver is drafted further, thereby increasing the length of the tapered portion. If the tapered portion is long, the piecing portion will be long and thin, which is not preferable. On the other hand, if the tapered sliver is removed and a new sliver of a normal fiber density is supplied, an excessively thick piecing portion will be formed when this sliver is entangled with the leading yarn.
In addition, in the conventional piecing method and apparatus, the leading yarn drawn out from the sliver guide entrance may be curled or folded by the twisting torque of the yarn or as a result of its contact with the nozzle. Under this condition, when fibers constituting a sliver are entangled with the leading yarn for piecing, a piecing portion will have an unstable form.
It is an object of this invention to provide a piecing method and apparatus for a spinning machine that solves the problems of said conventional piecing method and apparatus, and that can provide a piecing portion of an appropriate strength and form.